Thermoregulator



Feb. 21, 1950 w. D. LAVERELL ET AL THERMOREGULATOR Filed Jan. 27, 1947 THOMAS M WALTON FRIT MUM Patented Feb. 21, 1950 eTHERMOREGUIJATQR ZWi-IIiamID; 'LaverelLi'Norristown, axidjl'lhomasg M. Walton and"'FritzI H. Mumberg, ,IPhiladelphia, 5P2; assignors to' Precision Thermometer &;"In- F strument Company, -Philaide lphia,??Pa.;: ax crpo nation'of Pennsylvania- .="Am'ilicattionJ1Januaryv 27, 1947,.,,Seriali; No. 1724528 2.0m? invention iszan" improved thermo -regu1ator icomprisingi'iacsealed= tube containing aimagnetir-ctil lyra'idiustablei,solidiconductor 'and'a"liquid'eoniductor "of ivarirbletmassfforming *a thermally exjpansible izand "contractible column "making and ibrea'king Contact with the solid conductor to t make andbreaknn eleetriecincuit.

519m inventio :DroVides improved means "for Waryingithe *fiectivemass ofthe: liquid conducttorxandfior"thermally varyingthe length of the icolumn and means *for "magnetically adjusting "'the :so'lid fconductor frectilineerly and relatively the cbllumn so as to elf e ctirrelatively' coarse and fiflnexfldjustmentsofthe-settingbf the instrument *withont :opening the tubeiancl "withaminimum ftif f'fi'ictional;resistance. "Without impairing the :PeIectri'ca'I condu'cting path, and without permitttmgwontat between the "conducting liquid and *l-the means for"adjusting the" solid conductor.

*iOur "improvements provide an instrument which-may operate undersupermtmospheric or Faith-"atmospheric pressures and Which'is accufrat ly;akfiustableovera'wide'workingrange Withmntidarrgerof corroding; deteriorating or displacf'ing 'thermeehanism forza'djusting theisolici "con- .dlltOI', :without contaminating the liquid Y coniductor, and i-wi't'hout "stopping "the passages tthroughwhiehtthe-conductorsimove.

"llhe prinoiples and characteristic features of ionrfinvention, and It'hQmaIIIIGI -of"makin JCOnstructing *and using "onr improved "thermoeregu1ator vvwill further appear from the accompanying drawings and the:-"f-ollowing description exlTfi GJiTImEWheEbeSt mode. in which we have con- I i'tar y' viewidfiailongitud-inalsection of the thermorreguletorrshown; in Fig. -1 with the magnet look- :ing nutin unlocking "position Fig. '3 is a; trans- Werse sectional *view "taken on the line 3 3 Of 2; .Fig. 4. is a transversetseotional view taken :mttheilinefil-d: of Fig? 2; Fig. 7'5 -is 2mrenlau ged iifrqgmentary-Wiew :of the longitudinal section of tthe portion of the'i instrumentnonts'tinin afix-ed ac'ontact ucomfilementary to the adj-ustable solid ejcorfchictor; sand {Fig. 6 i is a, transverse sectional view taken ,onth '1ine'}6'6" of Fig."- 5.

the embodiment 16f "EOUI' .inventionaillu'strat- .1121 :the ffirawings, an :o1iter- :tube I iof glass :or tithe.like:hasyakbiilbronreservoir .2 'integralfomied eonithe'kbottomi-theredf and *commur'iicating with ea cafiillarfhore -3-o"f an inner tnbe fi havingan (Cl.'i'200-'+141) t-enlargeduupper "section "5 fforming "a chamber- B.

i A hollow .:qu'i11 or sleeve 11,- integrellyfformed on the tube '4 and containing an "extens'ion "of the capillarylborej ,g'projeots upwardly"f1tom the'bot- 5 tom ofthechamberffi'and terminatesm a'eup #8 having. an eccentric grimfifhaving "a po'rtion of .'its,perimeteriin sufii'ciently Close proximity to theflinner." surface of" the wall of the chamber fi to prevent passage "of mercury "between such .pperimetert portion'and the adjacentwall-"surface.

3A hollow ,quill orgsleeve I0 :is formed integrally :onthe f; top .of f thefttibe section *5 and "de- .pen'ds 7 into the chamber '6 to *a, :point ztdjacent .tolbutvspacedrfrom'the"top;oftthe'cup 8. The .bore of the flqu'ill I0 is aligned with the'cebi-llary bore 3.

lAitubu1ar,,,shel1 I I .is positioned inithe" tube I above the .tsection *5 :and "may be formed integra11y therewith i101 cemented-thereto by-a suit- .able :connetztingmnd tsealing member I2 r containing an .aperture aligned-"with the cabillary bore 3.

The. shell I I comprisesfho'llowsections |3 i8ind I4 connected .,by "an :intermediateineck I5 conitainin a longitu'dinalraperture I Grconnecti-ng-the interiors of "the sections I3 and I4 The bot- "tom wall of "theisection I3 is turned upward to "form a'hollow 'qu'ill or sleeve I'I; projectingsubstantially :above ':the bottom of the "section I3 and containing allongitudinal passage aligned with thecapillaryt3. (The-upper'wallzoftthei'sec- :tion l4 1 is drawn to :a "tip Iii-"through which. the :bharnbers :ilnitheimemberyt, i I3 and I4 mac-ybe exhaustedor gasi'under pressure"introducediinto ;,suc,hfichambersracndf thetip l'8-cthen 'sealed. imany usual manner.

'iThejpasseg-e. IG aprovidesi-a;smooth walledislfie weyiifor;1a" threa'cle'd:stemioriconductingscrew I9 "which" hasea tcon'jducting' rod 0r"wi1'-e I9 *fixed'ito the bottom "thereof "and "extendin it'hroughthe "apertures in Efthemerr'rbers I"! I2 and I0 into* the ::cup '8: andmapillary bore 3.

Aitriangular; plate 2 I is :aseate'd "on top 1 of the '.'neck I5 and is .i-securejd thereto by :downturned jZDI'O IES ZZ =tembedded in thezrneok and 'by-ra ita'il fi22 wllichexten'ds ithrough" the "well "of the sec- *tion [handintotheside "of the neck I=5=to1 form -a. looprtenhinal on which is-wrapped the end "of aconducting xvii-e 20 whieh enters ithe"in'stru- '50 meritithroughthe'cap 30.

The plate 2| contains an "aperture -through "whieh the; stem 5 9f is; screwed: so "thatizthe cplate 52 I makesfigodd ;-e1e 6trica1 contact with ttherifaces et (the 'thread 6f the :stem Hi9 and :%acts as an 55 elastically :mounted ssin'gle 's-thnead :nnt therefor.

, When the stem i9 is rotated it is screwed up or down through the plate 2| and is thereby moved longitudinally to move the conducting rod or wire I9 rectilinearly without impairin the circuit through the wire 20.

The threaded stem l9 has fixed to the upper end thereof a magnetically permeable head 23 of oblong or elliptical cross section forming an armature for an annular magnet 24 which encircles and makes a close slip fit with the periphery of the tube 1. The magnet 24 has diametrically opposite north and south poles of sufficient axial length to embrace a desired field of rectilineal movement of the armature 23 for varying the setting of the instrument without moving the magnet axially to any substantial degree.

The magnet 24 is suspended from a non-magnetic hub 25 having its upper end 26'exteriorly threaded for engagement by the threaded inner surface of a lock nut 21. The lock nut has a lip 28 overlying a flange 29 of the cap 30 which forms a closure for the top of the tube I and through which the lead-in wire 20 emerges for incorporation in a desired electric circuit to be controlled by the instrument.

A complementary lead-in wire conductor 3| enters the instrument through the cap 30, passes downward between the tube l and the inner tubular members, is wrapped around the tube 4 and around the radial headed boss 32 thereon, is twisted on itself, it passed through the aperture 33 of the boss 32, and sealed in the wall of the tube 4 with its end exposed in the capillary 3.

The exposed end of the wire 3| is below the lowest level to which the column of mercury or other conducting, thermally responsive, liquid in the bore 3 recedes and hence there is continuous contact between the conducting column and the conductor 31. The circuit through the conductors 2B and 3| is therefore closed when the meniscus of the mercury column contacts the bottom of the solid conductor or wire IS.

The temperature at which a given mass of mercury in the bulb 2 and bore 3 will cause the meniscus of the column to contact the wire l9 may be varied by varying the penetration of the wire l9 into the bore 3 and the temperature at which the solid and liquid conductors make contact may also be varied by varying the mass of liquid conductor in the capillary.

When it is desired to change by some small fraction of a degree the setting point or temperature at which apparatus in the circuit containing our improved instrument is actuated, the rodfi9 is moved relative to the meniscus of the liquid in the capillary tube 3. The magnetically permeable head 23 is held by the lines of magnetic force emitted from the permanent magnet 24 in a fixed position relative to said magnet. Hence, when the magnet 24 is turned, the head 23 is turned, and when the magnet 24- is held stationary the head 23 is also held stationary though the thermometer tube be turned. If the tube is turned while the magnet is held stationary and the nut 21 is loose, the stem I9 is fed through the plate 2|, thus varying the position of the rod l9 relatively to the meniscus of the liquid in the capillary tube. Slight turning will produce, accurately, extremely small variations in the actuating temperature.

If a greater changedn the setting point of the instrument is desiredthan is attainable by adjustment of the solid conductor l9, this may be effected by reducing or increasing the mass of 4 the liquid conductor in the bore 3. To reduce the mass, the bulb may be heated in a bath or appropriate temperature until a desired amount of mercury is discharged from the capillary into the cup, from which it may then be emptied.

To increase the mass of liquid conductor in the bore 3 without entrapping gas in the capillary, the rod i9 is withdrawn from the capillary by magnetically turning the armature 23, and the bulb 2 is heated until the capillary is completely filled or overflows slightly into the cup. The instrument is then turned on its side so that some of the excess conducting liquid in the spill chamber 6 fills the cup 8 at the head of the capillary tube and merges with the mercury in the capillary; the weight to mercury in the cup being sufficient to break the interfacial tension between such liquid and the surface of the liquid flush with the top of the capillary.

In filling the cup, the instrument is turned substantially horizontally, with the fiat edge of the rim 9 downward so that the liquid readily passes between it and the inner surface of the member 5. By turning the instrument on its axis some of the liquid is trapped by the proximityof the eccentric curved portion of the rim 9 with the inner surface of the member 5, so that when the instrument is again turned upright such trapped liquid flows into and fills the cup 8. Theinstrument may be then subjected to a cooling bath or other cooling means having a temperature of onev degree, or some other known increment, below the desired operating temperature and the liquid on contracting creates a suction which, together with the weight of the liquid in the cup surmounting the capillary tube, forces the liquid into the capillary tube and completely fills the same. The tube is then tilted so as to displace any excess liquid from the cup 8 and allow it to fall into the spill chamber 6. The capillary bore being filled, the temperature of the bath or other heat source is now raised, say, two degrees, or any known increment, above the desired datum temperature. This forces a small amount of the liquid from the capillary bcre into-the cup 8 and the spill is then emptied therefrom so that, when the bulb is subjected to the desired datum temperature, the meniscus of the column is slightly below the top of the capillary bore and the rod l 9' may be lowered in the manner describedinto contact with the meniscus in the bore to complete a circuit. v

The amount of excess liquid normally contained in the chamber 6 is preferably insufiicient to reach the opening in the quill [0 when the instrument is horizontal or inverted, and the bores of the quills l0 and I! are too small for the passage of liquid the'rethrough with the conductor l9 therein, even though the liquid should inadvertently reach a level above the mouth of the quill l0. Hence no free liquid can enter the hollow member l3 or passage It to contaminate or corrode the threaded stem [9, or nut 2!, or amalgamate therewith.

The instrument may thus be adjusted to within a tenth of a degree or within some other known increment of a degree, of the desired temperature, and still more accurate operation may be obtained by turning the tube or magnet so as to raiseor lower the rod l9 as above described.

By means of the conductors piercing but sealed in the inner shell, the one being connected with the stem I9 and the other withthe liquid, the meeting of the rod and the meniscus of the liquid will close an electric circuit while communication between outside and inside of the instrument other than by means of the wires is entirely out off because the inner shell is hermetically sealed.

By adjustments of the liquid mass and of the rod, coarse or fine adjustments of the instrument may be effected with extreme accuracy for controlling the closing and opening of an electric circuit through the rod and liquid column by making and breaking contact between them at predetermined temperatures, which may be varied widely.

Having described our invention, we claim:

1. A sealed instrument comprising a tubular member containing an apertured partition, a straight stem having a threaded surface and slidable through said aperture and guided by said partition, a nut having a member extending through the wall of said tubular member, said nut engaging said stem and coacting with the thread thereof to effect rectilineal movement of said stem, a liquid conductor complementary to said stem, and means for rotating said stem to ellect the rectilineal movement thereof.

2. A sealed instrument comprising a tubular structure containing a plurality of chambers spaced by apertured partitions, one of said partitions having hollow quills projecting therefrom in alignment with the aperture therein, a solid conductor movable through and guided by said last named partition and quills, a threaded member connected with said conductor and movable through and guided by the other of said partitions, magnetic means for operating said threaded member, a capillary tube projecting into one of said chambers and containing a liquid column in alignment with said solid conductor, and a surplus supply of conducting liquid in said last named chamber and excluded from said means by said quills and partitions.

3. A sealed instrument comprising a tubular member forming a bulb, a chamber and a capillary tube leading from said bulb and projecting into said chamber, said tube terminating in a cup having a perimeter partly in close proximity to and partly spaced substantially from the wall of said chamber above the bottom thereof, and a, liquid pool in said chamber and movable past said cup in one position of said instrument and obstructed by said cup in another position of said instrument.

4. A sealed instrument comprising a tubular member forming a chamber, a capillary tube terminating in a cup and a hollow quill projecting into said chamber in opposite directions and in alignment with one another, and a conducting liquid partly in said capillary tube and partly forming a pool in said chamber, said quill having a mouth free of said pool in all positions of said instrument and sealed to the passage of the liquid, and a solid straight conductor movable through said quill into contact with the liquid in said capillary tube.

5. A sealed instrument comprising a tube forming a bore containing liquid, means forming a spill chamber for receiving liquid from and supplying liquid to said bore to vary the effective mass of liquid therein, a rod rectilineally adjustable in said instrument relatively to said bore, magnetically operable mechanism for moving said rod rectilineally, and a partition having a quill projecting therefrom and encircling said section spaced substantially from said wall to permit passage of said liquid, a rod in said instrument and adjustable relatively to said bore, means within said instrument for moving said rod, and a shield for shielding said operating means from the liquid in said spill chamber.

7. An instrument comprising an outer sheath, a tube and a hollow shell Within said sheath, said shell being interiorly partitioned to form a plurality of chambers, a liquid in said tube means forming a partition having oppositely extending quills through which one of said chambers communicates with an end portion of said tube, a. rod adjustable through said means and quills aforesaid toward said tube, and means in the other of said chambers for moving said rod.

8. A sealed instrument comprising a structure containing a, plurality of chambers with partitions between them, one of said partitions being apertured and having a hollow quill projecting therefrom, a capillary tube having an open end housed in one of said chambers, a liquid in said tube magnetically operable means housed in another of said chambers, and a rod rectilineally movable by said means through said aperture and quill into said tube.

WILLIAM D. LAVERELL. THOMAS M. WALTON. FRITZ H. MUMBERG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,124,541 Singer et al Jan. 12, 1915 1,945,434 Greer Jan. 30, 1934 2,108,338 Juchheim Feb. 15, 1938 2,421,292 Schwartz May 2'7, 194'? FOREIGN PATENTS Number Country Date 270,503 Germany Feb. 16, 1914 

